Adjustable spring-mounted chair



Sept. 30, 1930. A. c. KORSTEN ET AL 1,777,204

ADJUSTABLE SPRING MOUNTED CHAIR Filed March 7, 1929 15 II J 9 19 g. a l D 0 ,7 C Mrsfen '9 7 (/2 W'sS T 1 pwem-rok;

Patented Sept. 30, 1930 UNITED STATES PATENT OFFICE ALBERTUS COENRADES Konsrnn AND MACHIEL DE VISSER, or no'r'rnnnnm,

NETHERLANDS ADJUSTABLE srnnve-iviounirnncnnrn Application filed March 7, 1929, Serial No. 345,066, and in the Netherlands March 17, 1928.

The invention relates to an adjustable, spring-mounted chair, e. g. an oflice-chair, the seat of which being revolving, adpistable in various heights and at the same tune spring-mounted.

The drawback of such chairs is, that the chair should be calculated for persons of different weight, while notwithstanding this the construction should be simple.

The chair according to the invention is arranged so that two springs are mounted 1n order to support the seat resiliently, which springs are put into action 1n succession, while one of them serves at the same time as a screw-worm for the height-adjustment of the chair, under the application of a clutch, mounted between said spring and the spindle of the seat, which clutch in released condition enables the seat to turn, without altering the height-adjustment of the chair.

The advantage of this is, that a simple and solid construction is obtained, whereas the person sitting on the chair, may turn without the height-adjustment of the chair altering.

The drawing illustrates by way of example the under-frame of the chair according to the invention, partly in section.

Preferably the construction is entirely made up of metal, in consequence of which the chair may be made in mass. The underframe of the chair according to the invention comprises a number, e. g. three legs 1 of tube metal, interconnected by e. g. two supporting yokes 2, 3, likewise made of tube metal.

The seat of the chair (which has not been drawn) is arranged on a rod 4 having a reduced end 5. On the place in which the diameter of the rod is reduced, there is an abutment 6 supporting the coiled spring 7 arranged round the end- 5 of the rod, which coiled spring rests with its lower side on a bottom 8 of a bush 9, enclosing the rod 5 and the spring 7.

The said bush 9 rests normally with its upper part against a ring 10 of the yoke 2, through which ring the rod 4 passes. The lower end of the bush 9 is mounted freely movably in an opening 11 of a ring 12 of the lower yoke 3. In some places near the upper edge of the bush 9, this bush is incised vertically so that in'those places a lip 13 is formed, which is bent outwardly and there upon somewhat shortened in case of need.

The lipsl3 are arranged so that they are discavity 18 in which a pin 19 may'rest which pin is inserted fittingly in an opening of the rod5.

The device according to .the invention. works as follows: i i

"In case one wishes to" adjust the chair according to the invention in the desired height, the seat is revolved in the same man neras a music stool, without taking seat on] the chair. Thereby the rod 4 revolves and the pin 19 of the end 5 laying in the cavity 18, takesalong with it the bottom portion 8-and at the same time the bush 9. Consequently the cams 13 between the convolution of the spring 14, which in that case acta s screw-worms,arescrewed downward so that the seat of thechair, together with the membersconnected-to it, sinks, since the bush 9 is adapted to sink freelythrough the opening 11 of the ring 12. y

As soon as the seat has substantially arrived at the desired height whereby the springs remain absolutely unstrained, one may take place on the chair. Hereby first of all the spring 7 is compressed. By this the pin 19 gets ofi the cavity 18 so that the seat may revolve in every direction without changing thereby the adjusted height of the chair, since the rod may rotate freely in the bush 9.

V A further advantage of this construction is that the Chair is calculated for the most varying weights of the persons using the chair.

With lighter persons only the weaker spring 7 is compressed. With heavier persons the stronger sprin 14 will be com pressed after the spring having been compressed to a certain degree.

In this manner a supple springing chair is constructed vina simple way, which chair is suitedifo; every weight and the seatof which may be revolved in all directions without altering anyhow the height-adjustment o6 thkawchair.

Moreover the construction the invention is cheap and easily to be made in mass, whereas its duration of life is very long.

We claim:

1. A device. of the class. described com: prising upper and lower rings,. arseatsu r eccording to porting. rodslidably associated with t e rings and having an abutment, abushing surrounding the rod end-having a bottom slidably receiving the-c rod a, coiled spring surrounding. the bushing, a lip carriedby:

the; bushing and engaged between the -helices of the springscoiled springin they bushing surrounding gthe rod and having its 1 upper vand lower en; engaging, respectively, A

the abutment and bu shipg bottomsaid; spring being of lesswstrength than; the first-qnamed spring, and a clutch connection between thew rod ,and' said bottom.

2. A device of the class described. comprising upper 'and lower I rings, a seat supporting rod slidably and rotatably; associ- Med with ,the rings, ,a bushing surrounding sprin encirclingt-he bushing, means for interloc ing the spring andthe lower. ring: at

lip carried by the bushing and engaged-hm tweenthe helices of said lspring -a; bottom q forthe bushing, said bottom having e cav-; itytherein, a pin-ca rriedby the rod, said;

in when engaged in the'cavity serving tow;

interlock the bottom; and ,rod to impart rotary movement to thebushing when the rod w is rotated, end to permit freerotationiof the rod uponld sengegement of the pin from-the cavity.

In testimony whereof we tures.

ALBERTUS COENRADES KORSTEN.-;

IACHIEL de VYI SSER.

- the rod and slidable in the lower ring, 21-; 

